The study, published in the British Medical Journal (BMJ), warned that Tamiflu could cause vomiting, which could lead to dehydration and the need for hospital treatment.

The researchers said children should not be given the drug if they had a mild form of the illness, although they urged parents and GPs to remain vigilant for signs of complications.

Parents of children with a compromised immune system or a condition such as cystic fibrosis should discuss the harms and benefits with their GP, they said.

But overall, the researchers said, children who were otherwise healthy could suffer more harm than benefit from taking Tamiflu or another antiviral, Relenza.

The researchers also found that using antivirals as a preventative measure had little effect – reducing transmission of flu by 8%.

The study was carried out in April and May, before the government decided to stop using Tamiflu preventatively.

Only those with suspected or confirmed swine flu were now getting the drug and are being urged to get access to Tamiflu through the pandemic flu service, which is accessed online or via a telephone helpline.

A Department of Health spokesman yesterday dismissed the researchers' claims that their findings would also apply to swine flu.

"The BMJ review is based on seasonal flu and not swine flu," he said.

"As the authors note, the extent to which the findings can be applied to the current pandemic is questionable – after all, we already know that swine flu behaves differently to seasonal flu, and past pandemics have hit younger people hardest."

Georgina, 16, was given Tamiflu when five pupils at Alleyn's school in south London were diagnosed with the illness in May.

"We saw a respiratory collapse through [the drug] and it almost cost my older child her life," her father said on GMTV.

"Nobody checked that she had swine flu beforehand. The Health Protection Agency just handed it out … and a lot of kids suffered in the school very heavily."

He went on: "The doctor's surgery wouldn't take her. The doctor said, 'No, we can't take her to A&E.'

"So she's just on the floor having this nightmare of a situation. A lot of people are in this situation. They don't know what to do."

Burnham told the presenter: "It must have been a very worrying situation for you, but that was in a very different phase of the illness when we were seeing the scenes from Mexico and we were in what we call the containment phase, where we were trying to isolate every case and then give Tamiflu to those around those cases.

"We've got to keep things in proportion and people shouldn't worry unnecessarily. People shouldn't take Tamiflu unless they have got swine flu."

Burnham said his message to parents was that they should not be worried if their child was taking Tamiflu for swine flu."